"""On This Day — a good thing that happened on today's date in history.

Source: Wikimedia's "On this day" feed (free, CC) — comprehensive, and it carries a
summary extract + thumbnail per event, which makes for a rich page. Multi-source ready
(a `source` column), so admin-curated entries and any future source slot in cleanly.

Pipeline (mirrors Daily Art): harvest today's MM-DD events → tone-filter to good/neutral
(keyword floor + optional LLM refine) → pool → deterministic daily pick → cached row.
All network/LLM work happens before any DB write, so the write txn is brief.
"""
from __future__ import annotations

import json
import re
import sqlite3

from . import daily
from .localtime import local_today

WIKI_BASE = "https://en.wikipedia.org/api/rest_v1/feed/onthisday/events"
_NO_REPEAT_POOL = 40          # pick from the N least-recently-shown for today's date

# Keyword floor: drop the obviously grim before the LLM ever sees it (and a safety net
# for when the LLM is unavailable). Substring match on a lowercased event text.
_NEG = (
    "war", "kill", "died", "dies", "death", "deaths", "dead", "massacre", "genocide",
    "disaster", "earthquake", "hurricane", "tsunami", "flood", "famine", "plague",
    "bomb", "attack", "assassinat", "murder", "shooting", "shot dead", "riot", "crash",
    "invad", "slaughter", "execut", "tragedy", "terror", "nuclear", "explosion",
    "sank", "sink", "wreck", "epidemic", "pandemic", "outbreak", "hostage", "coup",
)


# Wikimedia's feed hands us a 330px `thumbnail`, which upscales (blurry) in our hero. It also
# gives `originalimage` — a sharp, full-size URL that's always valid. We can't just request a
# bigger thumbnail width: for very large source images Wikimedia only serves pre-generated
# bucket sizes and 400s on arbitrary widths (e.g. 500px ok, 800/1024px fail, 1280px ok). So
# prefer the originalimage (reliably sharp), falling back to the thumbnail.
def _best_image(page: dict) -> str | None:
    """The sharpest reliably-served image URL: originalimage, else the 330px thumbnail."""
    orig = (page.get("originalimage") or {}).get("source")
    thumb = (page.get("thumbnail") or {}).get("source")
    return orig or thumb or None


def _fetch_events(md: str) -> list[dict]:
    """All events for a MM-DD from Wikimedia, normalized to our candidate shape."""
    mm, dd = md.split("-")
    data = daily.http_json(f"{WIKI_BASE}/{mm}/{dd}")
    out = []
    for e in (data.get("events") or []):
        text = (e.get("text") or "").strip()
        if not text:
            continue
        page = (e.get("pages") or [{}])[0] or {}
        out.append({
            "md": md,
            "year": e.get("year"),
            "text": text,
            "summary": (page.get("extract") or "").strip() or None,
            "image_url": _best_image(page),
            "page_url": (((page.get("content_urls") or {}).get("desktop") or {}).get("page")) or None,
        })
    return out


def _keyword_ok(text: str) -> bool:
    t = text.lower()
    return not any(neg in t for neg in _NEG)


def _llm_keep(client, candidates: list[dict]) -> list[dict]:
    """Ask the LLM which candidates are genuinely positive/neutral. On any trouble,
    keep the keyword-passed set (never lose the day to a model hiccup)."""
    lines = [f"{i}: {c['text']}" for i, c in enumerate(candidates)]
    user = (
        "These are 'on this day' history events. Return the indices of the ones that are "
        "GENUINELY UPLIFTING — a reader should feel a small lift of wonder, hope, or delight. "
        "Keep: discoveries, inventions, scientific breakthroughs, the arts and culture, "
        "exploration, human achievement, acts of courage or kindness, milestones of progress "
        "(rights won, things built, records set). EXCLUDE war, violence, disasters, death, or "
        "tragedy, AND exclude merely procedural or political-administrative events that carry no "
        "warmth (a coronation or accession, a treaty signing, an election, a law passed, a "
        "boundary or office change). When unsure whether something is truly uplifting, leave it "
        "out.\n\n" + "\n".join(lines) +
        '\n\nReply with JSON only, exactly: {"keep": [<indices>]}'
    )
    txt = client.chat_text([{"role": "user", "content": user}])
    m = re.search(r"\{.*\}", txt, re.S)
    if not m:
        return candidates
    keep = json.loads(m.group(0)).get("keep", [])
    idx = {int(i) for i in keep if str(i).lstrip("-").isdigit()}
    sub = [c for i, c in enumerate(candidates) if i in idx]
    return sub or candidates


def _tone_filter(candidates: list[dict], client=None) -> list[dict]:
    kept = [c for c in candidates if _keyword_ok(c["text"])]
    if client and kept:
        try:
            kept = _llm_keep(client, kept)
        except Exception:  # noqa: BLE001 — LLM is best-effort; keyword floor stands
            pass
    return kept


def _pool_count(conn: sqlite3.Connection, md: str) -> int:
    return conn.execute(
        "SELECT COUNT(*) FROM onthisday_pool WHERE md=? AND blocked=0", (md,)
    ).fetchone()[0]


def harvest(conn: sqlite3.Connection, md: str | None = None, client=None) -> dict:
    """Fetch + tone-filter today's MM-DD events into the pool. Per-day, idempotent
    (dedup by content key). Non-fatal on network failure."""
    md = md or local_today()[5:]
    try:
        events = _fetch_events(md)
    except Exception:  # noqa: BLE001
        return {"md": md, "fetched": 0, "kept": 0, "added": 0, "pool": _pool_count(conn, md)}
    kept = _tone_filter(events, client)              # all network/LLM done before the write
    before = _pool_count(conn, md)
    conn.executemany(
        "INSERT OR IGNORE INTO onthisday_pool (source, md, year, ckey, text, summary, image_url, page_url) "
        "VALUES ('wikimedia', ?, ?, ?, ?, ?, ?, ?)",
        [(c["md"], c["year"], daily.content_key(c["md"], c["year"], c["text"]),
          c["text"], c["summary"], c["image_url"], c["page_url"]) for c in kept],
    )
    conn.commit()
    after = _pool_count(conn, md)
    return {"md": md, "fetched": len(events), "kept": len(kept), "added": after - before, "pool": after}


def _candidates(conn: sqlite3.Connection, md: str, avoid: int | None = None) -> list[int]:
    """The pick pool for a date: if admin has featured any, pick only among those;
    otherwise the N least-recently-shown. `avoid` drops a specific id (admin re-pick)
    unless it's the only option."""
    featured = conn.execute(
        "SELECT id FROM onthisday_pool WHERE md=? AND blocked=0 AND featured=1 ORDER BY id", (md,)
    ).fetchall()
    if featured:
        ids = [r[0] for r in featured]
    else:
        rows = conn.execute(
            "SELECT id FROM onthisday_pool WHERE md=? AND blocked=0 "
            "ORDER BY shown_at IS NOT NULL, shown_at, id LIMIT ?",
            (md, _NO_REPEAT_POOL),
        ).fetchall()
        ids = [r[0] for r in rows]
    if avoid is not None:
        ids = [i for i in ids if i != avoid] or ids
    return ids


def pick_daily(conn: sqlite3.Connection, feature_date: str | None = None, force: bool = False,
               avoid: int | None = None) -> dict | None:
    """Pick + cache today's fact. Idempotent (skips if today's done unless force).
    Returns the stored row, or None if the pool has nothing for today's date."""
    feature_date = feature_date or local_today()
    md = feature_date[5:]
    existing = conn.execute("SELECT * FROM daily_onthisday WHERE feature_date=?", (feature_date,)).fetchone()
    if existing and not force:
        return dict(existing)
    ids = _candidates(conn, md, avoid)
    if not ids:
        return None
    pick_id = daily.seeded_order(ids, feature_date)[0]
    row = conn.execute("SELECT * FROM onthisday_pool WHERE id=?", (pick_id,)).fetchone()
    conn.execute(
        "INSERT INTO daily_onthisday (feature_date, pool_id, source, md, year, text, summary, image_url, page_url) "
        "VALUES (?,?,?,?,?,?,?,?,?) "
        "ON CONFLICT(feature_date) DO UPDATE SET pool_id=excluded.pool_id, source=excluded.source, "
        "year=excluded.year, text=excluded.text, summary=excluded.summary, image_url=excluded.image_url, "
        "page_url=excluded.page_url",
        (feature_date, row["id"], row["source"], row["md"], row["year"], row["text"],
         row["summary"], row["image_url"], row["page_url"]),
    )
    conn.execute("UPDATE onthisday_pool SET shown_at=? WHERE id=?", (feature_date, pick_id))
    conn.commit()
    return dict(conn.execute("SELECT * FROM daily_onthisday WHERE feature_date=?", (feature_date,)).fetchone())


def get_today(conn: sqlite3.Connection, feature_date: str | None = None) -> dict | None:
    """Today's fact if present, else the most recent (the room is never empty)."""
    if feature_date:
        row = conn.execute("SELECT * FROM daily_onthisday WHERE feature_date=?", (feature_date,)).fetchone()
        if row:
            return dict(row)
    row = conn.execute("SELECT * FROM daily_onthisday ORDER BY feature_date DESC LIMIT 1").fetchone()
    return dict(row) if row else None


def run_daily(conn: sqlite3.Connection, client=None) -> dict:
    """Cycle entry point: ensure today's date has a pool, then ensure it has a pick.
    Bounded + non-fatal — safe to call every cycle (no-ops once the day is picked)."""
    md = local_today()[5:]
    harvested = None
    if _pool_count(conn, md) == 0:
        harvested = harvest(conn, md, client)
    picked = pick_daily(conn)
    return {"md": md, "harvested": harvested, "picked": picked["text"] if picked else None}